A kind of cylindrical lock, this lock able to be installed on a door, includes: one transmission structure which can operate a drive base, this drive base gearing a latch mechanism; this latch mechanism having: one tubular shaped element, which can be coupled to a handle for actuation; a tube, which can be rotated and inserted into the tubular shaped element; one pushing part, having one side with at least one pushing section, this pushing section able to push the drive base at the appropriate time; a collar, which can be set on one end of the tubular shaped element, a meshing section formed on one end of the collar; an engaging element, partly installed in this pushing part, one meshing section formed on this engaging element, and this engaging element having at least one pushable section; one rotating part, having at least one pushing portion, each pushing portion at the appropriate time pushing the adjacent pushable section of the engaging element; one lock set, having a lock core linked to one transmission part; rotating this lock core to move from the beginning position at an angled position in a predetermined direction back to the beginning position, the transmission part of this lock set can push a moving part, causing this engaging element to do axial displacement, and causing the meshing section of the engaging element to be positioned and move between the incompatible meshing of the first position or compatible meshing of the second position, on the meshing section of this collar.